You can use this sample code for communicate with parse using rest api. And you can login to facebook.
IOS and Android Multiplatform
Kindly Note: We update new contents like WordPress Themes, Plugins, PHP Scripts everyday. But remember that you should never use this items in a commercial website. All the contents posted here for development & testing purpose only. We’re not responsible for any damage, use at your own RISK! We highly recommend to buy Parse Module + Sample Code from the The Developer ( mkaradil ) website. Thank you.
Download = Parse Module + Sample Code-[Updated].zip